Luqing Cui was appointed to a postdoctoral position in the Division of Engineering Materials, and joined the team in November 2019. Two years of intensive work has resulted in eight peer-reviewed articles. This is an impressive accomplishment for a young researcher at the beginning of his career.
Additive manufacturing (AM), with its unique advantages of design freedom and rapid manufacturing capability, has gained huge scientific interest. Researchers all over the world are examining the limits of the technology, and finding new approaches to fill knowledge gaps. They are seeking to fully understand the materials used in additive manufacturing.
Cellular structure and exposure to load
Luqing Cui studies the fatigue properties of AM alloys. Fatigue is a process that leads to mechanical failure, and it results from the application of repeated cyclic stresses. In other words he studies how the unique microstructure in the material, especially the solidification of cellular structure, is affected by the continual and repeated loading.
“Many people study additive manufacturing. My research is mainly about the relationship between microstructure and the mechanical properties of additive manufacturing materials. My focus is entirely on deformation and failure mechanisms.”
To be able to introduce AM for critical and highly loaded metallic products, we need a deeper understanding of the processes and materials.
“There are many studies on cellular structure and tensile properties, but only a few have looked at the fatigue properties. These are more complex than tensile properties, and are usually encountered when studying engineering materials in practical use”, says Luqing Cui.
The research group at Linköping University has collaborated with industry for many years to study the performance of the AM materials used in demanding applications in the aerospace and gas turbine industries. Even small changes in the proportions of the elements in an alloy composition can lead to significant changes in behaviour and performance.
“We need to know if a material is reliable or not, and this means that we must do tests. In our lab we look at fatigue processes at high temperatures. We perform creep tests at 1000 degrees, and high-pressure tests at 300 megapascal. We look at how much time it takes to reach failure, and how the microstructure evolves during the deformation process. This information also helps us suggest how the microstructure can be adjusted, and mechanical properties improved, for alloys in the future.”